Constraints on a seesaw model leading to quasidegenerate neutrinos and signatures at the LHC

TL;DR

This paper investigates a TeV-scale seesaw model with quasi-degenerate neutrinos, analyzing constraints from vacuum stability and lepton flavor violation, and explores the potential for discovering heavy neutrinos at the LHC through tri-lepton signatures.

Contribution

It introduces a specific seesaw model with quasi-degenerate neutrinos, constrains its parameters using vacuum stability and lepton flavor violation data, and evaluates its LHC discovery prospects.

Findings

Vacuum stability imposes significant bounds on Yukawa couplings.

Lepton flavor violation further constrains the model parameters.

Heavy neutrino signatures could be observable at the 14 TeV LHC with tri-lepton final states.

Abstract

We consider a variant of TeV scale seesaw models in which three additional heavy right handed neutrinos are added to the standard model to generate the quasi-degenerate light neutrinos. This model is theoretically interesting since it can be fully rebuilt from the experimental data of neutrino oscillations except for an unknown factor in the Dirac Yukawa coupling. We study the constrains on this coupling coming from meta-stability of electro-weak vacuum. Even stronger bound comes from the lepton flavor violating decays on this model, especially in a heavy neutrino mass scenario which is within the collider reach. Bestowed with these constrained parameters, we explore the production and discovery potential coming from these heavy neutrinos at the $14$~TeV run of Large Hadron Collider. Signatures with tri-lepton final state together with backgrounds are considered in a realistic simulation.